Pressure relief vent



Nov. 10, 1942. w, BUSHNELL 2,301,365

PRESSURE RELIEF VENT Filed March 6, 1940 DONALD MBUSH/YELL IN VENT OR(mm-m BY A TTORNE YS enclosure.

Patented Nov. 10, 194 2 UNITED ST'EES rnEssURE RELIEF VENT Donald W.Bushnell, Rochester, N. Y., assignor to Eastman Kodak Company,Rochester, N. Y., a corporation of New Jersey Application March 6, 1940,Serial No. 322,585

3 Claims.

This invention relates to pressure relief vents of a type which may bebuilt into a machine, building or other closure, in which volatilesolvents or other readily combustible materials may be handled.

One object of my invention is to provide a relief vent which isinsulated so that temperatures inside of the closure may be readilycontrolled. Another object of my invention is to provide a relief ventdesigned so that an extremely slight increase in pressure may cause therelief vent to open and to relieve the pressure inside of the Anotherobject of my invention is to provide a relief vent constructed offireproof materials which are light in weight and which can readily bekept perfectly clean. Another object of my invention is to provide arelief vent in the form of a window, there being a closure for thewindow made of light-weight material which is movably mounted withrespect to the window so tures being particularly pointed out in theclaims at the end thereof.

Coming now to the drawing wherein like reference characters denote likeparts throughout:

Fig. 1 is a top plan view, partially broken away,

showing a pressure relief vent constructed in accordance with andembodying a preferred form of my invention.

Fig. 2 is an enlarged sectional view taken on line 22 of Fig. 1, butshowing the part broken away in Fig. 1.

Fig. 3 is an enlarged fragmentary detail of a preferred type of hingewhich may be used in connection with the relief vent shown in thepreceding figures. I

Fig. 4 is a fragmentary detail elevation showing a modified form ofcover support.

In Patent No. 1,930,138, Van Derhoef, for Explosion vent, grantedOctober 10, 1933, there is shown an explosion vent over which thepresent application is an improvement. In the Van Derhoef patent, theexplosion vent consisted of a flexible sheeting which is preferably madeof transparent material and whichmay be of cellulosic material,impregnated fabric, rubber or other suitable sheeting. When thissheeting is distorted by pressure within an enclosure, it is brought incontact with a series of sharp teeth designed to facilitate rupturing ofthe material to relieve the pressure on the enclosure.

lief vent which is also designed to relieve pressure and which differsfrom the Van Derhoef construction primarily in providing an insulatedcovering for the opening to control temperatures inside the enclosureand to provide a light-weight all-metal vent which will worksatisfactorily at comparatively small differences between the pressuresinside and outside of an enclosure.

Referring to the drawing, the enclosure which may consist of a building,machine, or other enclosure, may include walls I and in such walls Iprovide one or more pressure relief vents, each of which may consist ofa window 2, formed in a wall of the enclosure, this window preferablyincluding a frame 3 which may extend around the window 2 and which maybe attached thereto by means of a frame 4 through which screws 5 maypass into the tapped openings 6 in the frame member 3.

Iprefer to provide a gasket 1 which may be of a well known typeincluding a woven cloth tape in which wires are inserted, the tape beingbound by a heat setting cement. Such a gasket is preferably used to makea gas-proof joint between the frame 3 and the wall I.

I prefer to provide the window frame in two sectionsthe section 3 abovedescribed and a second section 8, this section being preferably attachedto section 3 by means of screws 9 entering the tapped holes ID in theframe 3. It is convenient in setting up a window frame to use shortdowel pins II for properly registering the frames 3 and 8, and these mayor may not be used, as desired.

In order to form a gas-tight joint between the frames 3 and 8, I providea molded rubber gasket [2 which extends completely around one of theframe members here shown as frame member 8, having a dovetail connectionwith and being held in position by the dovetail slot l3. This gasket hasa roundedouter edge It which engages a complementary shaped groove [5,so that when the frames 8 and 3 are screwed together, they form agas-tight connection.

The frame 8 is preferably provided with a series of downwardly extendingbrackets [6, each of which has an inwardly extending flange l1, thisflange being adapted to position and support a rigid cover member [8.This cover member may be in the form of a box-like housing consisting ofa bottom wall [9 with upstanding side walls 20, these side wallspreferably being formed over at 2i to form a sufficiently thick wall toIn my present invention, I have provided a re- 55 receive screw threadsso that screws 22 may fasten the downwardly extending flanges 23 of acover member 24 securely in place. a

The screws 22 are preferably provided with means for preventing theircomplete removal, such as drops of solder 25, so that when the screwsare backed out, the cover member 24 may be removed, since the screwsmerely pass through slots in the flanges 23.

The shallow, box-like receptacle is preferably made of light-weightmetal, such as thin aluminum sheeting, and it is preferably filled withan insulating material 26.

It is frequently desirable to control the temperature in an enclosurewhich may contain volatile solvents, and it is always desirable to pre--vent dust or dirt from entering into such an enclosure. Therefore, Iprovide the insulation 26 by utilizing a plurality of layers of crumpledbright metal foil, such as aluminum foil, because this material forms asatisfactory insulating material and is not liable to produce dust.Moreover, the aluminum foil is totally enclosed in the rigid member bythe aluminum sheeting forming the box-like enclosure.

The rigid member may be provided with a means for restraining themovement of this member if it is suddenly moved through a change inpressure. Such means may consist of chains 27, attached to plates 28 bymeans of bolts 29 passing through the rigid member. These bolts may passthrough a sleeve 39 and a cottor pin 3| passing through the bolt andsleeve may allow the nut 32 and the plate 23 to be removed, so that thecover member 24 may be removed without rcmoving the bolts from theshallow, box-like structure.

The outer walls of the rigid cover member I9 are of substantially thesame shape as the window frames 3 and 8, but the size is such that aspace remains between the edges of the rigid member and the windowframe. This space is completely covered by a sheet 35 of thin aluminumfoil which may be conveniently made .001 thick and which is preferablyof dead soft material. Such fcil is, of course, quite flexible, so thatas the gas pressure inside of the enclosure builds up, it may flexoutwardly. Such flex-ing causes themetal foil to engage thesawtooth-like edgesfil on the plate 35 which extend completely aroundthe window frame 8 and assist in rupturing the thin, flexible, readilyfrangible sheet 35. It is only necessary of the sheet 35 to cover theopening between the rigid member and the window frame. However, since itis not always easy to make a gas-tight joint with seal-ing strips justcovering this opening, I find it most convenient tov use a single sheetof material 35 and to cement it to the entire top of the rigid member I3and to fasten the four edges tightly to the window frame 8 by means'of aseries of strips I31, one extending along each of the four sides of thewindows. These strips I37 may be attached by screws 3% to the windowframe 8, and I. preferably include beneaththe strips IS! a gasket 3i!vwhich may be rectangular and made in one piece, or which may be made offour strips tightly fitted at the corners. This gasket may be of thesame material as the gasket I.

In use, as many of these pressure relief vents may be provided as arenecessary for the size of the enclosure. When pressure suddenly buildsup in. the enclosure, the entire rigidv cover member I9, moves upwardly,away from its supporting brackets, I6, immediately drawing the four,edges of the flexible sheeting 35 against the saw teeth LII 37, severingthe metal foil and relieving the pressure. Normally, the chains 27 willbe sufficient to prevent the rigid member I9 from moving far from thepressure relief vent and thus possibly damaging other parts of theenclosure or injuring workmen. However, if there is only a very slightincrease of pressure, it is possible for the metal foil 35 to flexsufficiently to rip out at one or more places to relieve pressure. Insuch case, the rigid closure member I9 may move only slightly upon itsbracket I8, or may not even move at all. If it moves only slightly, thebeveled guiding edges LII] of the bracket I6 will permit the rigidmember I9 to again seat itself on the flanges Il unless, of course, therigid member I9 is moved completely away from the window frame 8. In anyevent, the beveled edges Ml facilitate placing the rigid member I9 inreturning it to its original position after a pressure change hasoccurred.

It is frequently necessary to utilize the windows 2 for manholes, sothat workmen can enter the machine or enclosure for repairing, cleaningor other purposes. It is for this reason that the window frames are madein two sections 3 and 8, so that the frame 8, with the bracket I5, andthe rigid member I9 may all be moved relative to the frame 3 to permitworkmen to enter the window 2. For such purposes, I have sometimes foundit convenient to provide a pair of hinge plates 5%! of the special shapeshown in Fig. 3. In this case, the window frames 3 and 8 lie adjacent toan upstanding wall IIlI of the enclosure, which is an extension of thewall I, and the frame 3 is equipped with the plate 56 which may beattached by screws M. This plate is provided with a slot 52 in the shapeof an inverted J, to receive a pin 53 of the frame 8 serving as a hingepmtle. In order to open this window, the screws 9 are taken out of theframe 8, so that this frame may be moved vertically with respect to theframe 3, raising the pin 53 up in the slot. As soon as the frame hasbeen removed from the dowel pins I I, the pin may be swung around thecurved portion of the slot 52 to rest in the end notch 54 and the entirecover member I 9, with its associated parts, can be swung about thisportion of the plate as a hinge, so that the cover does not need to bedisassembled except as above described.

I have described a preferred form of pressure relief vent in which thevents are arranged on the top or substantial horizontal wall of the ma:chine. I have found thi generally the most desirable location for suchvents, but it is also possible to make such vents in various different10- cations, and to provide them on vertical or other walls, in whichcas the shap of the bracket I3 must be altered to suit the particularposition, or the rigid member I9 may be provided with a special type ofhinge member, as indicated in Fig. I, which will support the weight ofthe rigid member I9 and permit it to swing outwardly upon an increase inpressure. As indicated in Fig. 4, the cover member IE9 may be attachedto the hinge members I25 by suitable bolts IZI, this hinge member beingadapted to turn about a pintle I22 of the hing member I25 attached tothe frame member I It. In this case, of course,,it is not necessary toprovide chains 2'! to restrain the movement of the rigid member, becausethis will be done by the hinge members.

It will be noticed that in any case the rigid closure member I9 is wellinsulated, and since there is a bright metal foil sheet totallycoveringth complet window 2, there is comparatively little heat exchangeoccurring at the places where these explosion vents are provided in themachine, so that it is possible to carefully regulate the temperature ofthe enclosure where this is necessary.

What I claim is:

1. An explosion vent comprising in combina tion, an enclosure includinga wall, a window in said wall, a frame extending about said window,brackets supported by the frame, and a closure for the window comprisinga cover adapted to rest on the brackets and including a plurality oflayers of bent, light-weight metal foil contained in a light-weightmetal container and a thin sheet of readily rupturable metal extendingcompletely over the cover and attached to the frame,

whereby pressure in the enclosure may move the said wall, a frameextending about said window, a closure for the window, hinges supportingan edge of the closure from an edge of the frame, and a thin sheet ofreadily rupturable metal extending completely over the closure for thewindow and attached to the frame, whereby pressure in th enclosure maymove the closure for the window, rupturing the thin sheet of rupturablemetal to release pressure in said closure.

3. An explosion vent comprising, in combination, an enclosure includinga wall, a window in said wall, a frame extending about said window, aclosure for the window, insulation carried by the closure, hingessuspending an edge of the closure from an edge of the frame and a thinsheet of readily rupturable metal extending completely over the closurefor the window and attached to the frame, whereby pressure in theenclosure may mov the closure for the window rupturing the thin sheet ofrupturable metal to release pressure in said closure.

DONALD W. BUSHNELL.

